Phương trình \(\cot \left( {2x - \frac{\pi }{6}} \...

C

- Hướng dẫn giải

ĐK: 

\(\begin{array}{l}
\sin \left( {2x - \frac{\pi }{6}} \right) \ne 0\\
 \Leftrightarrow 2x - \frac{\pi }{6} \ne k\pi \\
 \Leftrightarrow x \ne \frac{\pi }{{12}} + k\frac{\pi }{2}
\end{array}\)

\(\begin{array}{l}
\cot \left( {2x - \frac{\pi }{6}} \right) = 0\\
 \Leftrightarrow \cos \left( {2x - \frac{\pi }{6}} \right) = 0\\
 \Leftrightarrow 2x - \frac{\pi }{6} = \frac{\pi }{2} + k\pi \\
 \Leftrightarrow x = \frac{\pi }{3} + k\frac{\pi }{2}
\end{array}\)